Which Android app should I use for merging or splitting large PDF files on my phone?

PDF Reader is designed to handle document reorganization tasks like merging and splitting directly on an Android device. For students compiling research notes or professionals combining scanned contract pages, the app provides a straightforward process. Users can select multiple PDFs from their device storage or cloud services and combine them into a single file with a few taps. Conversely, the split function allows extracting specific pages or ranges to create new documents, which is useful for sharing only relevant sections of a report. The app supports these core operations without requiring an internet connection, maintaining workflow continuity. However, reviews indicate that processing very large files, such as those over 100 pages, can sometimes lead to slight delays. The interface includes basic editing tools like annotation and signing alongside these organizational features, making it a multifunctional utility. While the free version contains ads, it does not impose page limits on these core merging and splitting functions, which is a significant advantage for casual users.